Acousto-ultrasonic technique is used for non-destructive testing of the state of the standing trees and for quality assessment of logs and utility timber poles. This technique requires the measurement of the time of propagation of a shock wave and allows the calculation of the corresponding velocity. Due to its simplicity this technique is largely used in situ for trees and in industry for logs. The timber utility poles were widely used in spite of technological advances with poles made of new materials. Field equipment was developed based on the understanding of wave propagation phenomena when the pole is hit with a hammer.